Machine for forming sheet metal elbows



Oct. 29, 1940. c J HQLUB 2,219,993

MACHINE FOR FORMING SHEET METAL ELBOWS Filed July 4, 1959 7 Shets-Sheet 1 in U llllll 1 INVENTOR. @9 BY ATTORNEY r o M ig:

Dill Oct. 29, 1940. c J HOLUB 2,219,993

MACHINE FOR FORMING SHEET METAL ELBOWS Filed July 4, 1939 7 Sheets-Sheet 3 1.50 148 6 INVENTOR.

g J BY M gamnw Oct. 29, 1940. c, HQLUB 2,219,993

MACHINE FOR FORMING SHEET METAL ELBOWS Filed July 4, 1939 7 Sheets-Sheet 4 rlm J My a/wne ATTORNEYS Oct. 29, 1940. c, J. HOLUB 2,219,993

MACHINE FOR FORMING SHEET METAL ELBOWS Filed July 4, 1939 7 Sheets-Sheet 5 .fllili v INVENTOR. v BY W ATTORNEYS A 0a. 29, 1940. H L 2,219,993

MACHINE FOR FORMING SHEET METAL ELBOWS Filed July 4, 1939 7 Sheets-Sheet 6 villi/A Oct. 29, 1940.

C. J. HOLUB MACH INE FOR FORMING SHEET METAL ELBOWS 7 Sheets-Sheet 7 I iill I is l\ IIIIIIIIIIIIIIIJ IIII/II/IIIII INVENTOR.

Z TTORNEYJ Patented Oct. 29, 1940 UNITED STATES MACHINE FOR FORMING SHEET METAL ELBOWS 7 Charles J. Holub, Columbus, Ohio Application July 4, 1939, Serial No. 282,795

3 Claims.

This invention relates to an improved machine for producing corrugated stove pipe elbows. More particularly, the invention relates to an apparatus for operating upon a sheet metal tube or pipe for circumferentially corrugating the same and, as the corrugations are made, progressively bending the tube at the corrugations to procure the desired elbow angle.

This invention relates to the type of machine disclosed in myv previous patent, No. 1,553,817, granted September 15, 1925. It has been my object to simplify the machine and to increase its efficiency and speed. Accordingly, the invention resides in the provision of any one of the several features hereinafter enumerated.

First, provision has been made for operating the pipe feeding mechanism, the corrugating mechanism, and the bending mechanism from a single power driven shaft.

Second, the feeding mechanism consists, primarily, of an actuator unit, conveniently accessible and removable.

Third, the corrugating die arrangement has been provided entirely at the forward end of the machine with its drive taken from the main drive shaft, by means of a simple crank shaft mechanism.

Fourth, the dies, which are of plate or knife form, have been compactly interrelated and braced so as to operate at high speed without defiection and so as to form the corrugations uniformly circumferentially.

Fifth, the actuating mechanism for the bending means has been taken from the main drive shaft from an adjustable treadle arrangement, compactly organized and conveniently removable as a unit with but little disassembly.

Sixth, the manually operated means for clamping the pipe in the carriage, for disengaging the carriage from the ratchet bar and for moving the carriage to starting position has been more compactly arranged, and

Seventh, the controls for connecting the carriage to the driving means and for starting and stopping the operation of bending an elbow have been greatly simplified.

Other objects and certain advantages will be more fully apparent from the description of the drawings in which:

Figure 1 is a side view of the improved elbow bending and corrugating machine of this invention.

Figure 2 is an enlarged fragmentary front view of the machine illustrating the corrugating dies and bending apparatus.

Figure 3 is a top plan view of the machine showing a length of pipe in position and the apparatus being tripped for starting the bending and corrugating operation.

Figure 4 is a sectional view of the machine taken on lines 44, Figure 3, illustrating the general arrangement of the corrugating dies.

Figure 5 is a sectional view taken on line 55,

Figure 2, but showing the elbow partially corrugated and bent with the dies in position for forming a corrugation.

Figure 6 is a sectional View taken on line 6-45, Figure 4, illustrating a part of the construction of the upper die.

Figure '7 is a sectional view taken on line '|--'1, Figure 4.

Figure 8 is a sectional view taken on line 8-8, Figure 3, showing the means for controlling the power connecting clutch.

Figure 9 is a front view of the carriage which supports and feeds the pipe.

Figure 10 is a sectional view of the forward or bending head, which is engaged on the forward end of the pipe and through which the bends are successively made,

Figure 11 is a perspective view of the tool used for adjusting the carriage or head for receiving pipe of different diameters.

Figure 12 is a sectional and fragmentary view taken on line [2-42, Figure 3, detailing the carriage or head and illustrating diagrammatically the feed control mechanism therefor.

Figure 13 is a front view of the carriage or head partially in section for illustrating a variation in the setting of the head for receiving a pipe of medium diameter.

Figure 14 is a fragmentary partially sectional view illustrating the carriage feeding mechanism.

Figure 15 is a sectional view taken on line l5-|5, Figure 3, showing the clutch control means.

Figure 16 is a sectional view taken on line Iii-l6, Figure 15, detailing the clutch.

Figure 17 is a sectional view taken on line |'|-l'|, Figure 16, illustrating the clutch in top plan view.

Figure 18 is a sectional view taken on line I8-l8, Figure 1, illustrating the operating means for the elbow bending mechanism.

The machine of this invention operates upon straight lengths of pipe and is effective for corrugating and bending the pipe in the form of an gressively corrugated and bent with each bending operation succeeding a corrugating operation.

The bending force is applied to the pipe through the medium of a bending head or ring engaged upon the outer end of the tube. This head is swung in progressive steps through an are by means of arms engaging the'head and swinging as a unit at an angle to the direction of feed of the pipe. These arms are mounted so as to swing apart to permit the insertion and withdrawal of the tube or elbow with the bending head attached.

The inner end of the tube is fixed to the carriage and the carriage moved to a starting position from. where the feeding, corrugating, and bending power is automatically continued until the elbow is formed. At this time, the power is tripped and the elbow removed. The machine is designed to operate at a high rate of speed, making it possible to produce elbows at the rate of four a minute.

Referring to the drawings, the machine includes a bed 2%, supported on front and rear supporting legs 2!. The lower ends of the legs are joined and spaced by means of tie rods 22-22. The bed provides a forward supporting frame or wall 23 integral therewith. At the rear end, a supporting bracket 24, representing the rear wall of the upper part of the machine, is attached.

The described parts are attached together by means of bolts 25. The feet of the supporting legs are attached to the floor by means of bolts 26.

The power is delivered to the rear end of the machine. The main power shaft 2'? is journalled in the end brackets 232@ and extends longitudinally of the machine. All three of the movements, that is, the carriage feeding, the bending and the corrugating movements, are taken directly from this power shaft Zl. The power is derived from an electric motor 28 fixed to the floor and driving the large pulley 29 through its small pulley 30 and a multiple belt arrangement 31. Brackets 23 and 26 provide appropriate bushing elements 3232. in which the shaft 2'! is journalled. The pulley29 is loosely journalled on a bushing 33 on the extended rear end of the power shaft. A clutch 3 is mounted on the shaft between this pulley and the frame or bracket element 24. v

The clutch consists of a body member 35 fixed to the shaft by means of a key 38 (Figure 18). This clutch member includes an annular groove 3'1 crossing a longitudinal slot 38. A clutch coupling key .39 is slidably mounted in the groove or slot 38 and has its extended rear end normally held in clutching position by' means of a coil spring 40 disposed under compression between the key and the forward wall of the clutch body. The clutching end of this key engages a clutching tooth 4! formed integrally with the pulley wheel 29. This type of clutch provides an engagement and disengagement at the same point of revolution so that the clutch is disengaged after a complete cycleof operation, that is, the

power can not be disengaged while the die plates are in the corrugating position.

The clutch is controlled by means of an arm 42 (Figure 15) pivotally mounted at one side of the bracket on a pivot bracket This arm has its inner end tapered (Figure 17) so as to provide a cam surface M engaging a corresponding cam surface 45 of the key 39. As the element 35 rotates, it will cause the inclined surface 15 of the key to engage the cam end M- of the lever thereby forcing the key out of its engagement with the clutching tooth fill, assuming, of course, that the lever has been dropped into the annular groove. A link 4'5 connects the intermediate portion of this arm with the outer end of an arm 41 fixed to the control rod d8 by means of a key Q9.

Control rod' 38 is rotatably mounted on the frame members 23, 24, longitudinal of the machine. An actuating arm 56 is fixed to the control rod 28. This arm extends laterally into engagement with the surface of a cam 5i, fixed to a shift rod 52, slidably mounted parallel with the control rod in end brackets 53, secured to the main frame members 23, 24. The cam surface of the cam engages the cam surface of the arm 5%, as shown in Figure 8.

The shift rod 52 also carries a hand lever 54, extending upwardly to a position where it is conveniently grasped. An arm 55 (Figure 3), which automatically couples and uncouples the power, ext'ends laterally from the carriage 56 to a point just beneath the shift rod 52 where it will engage the cam or trip dog Ed at the rear end of the retreat stroke of the carriage, and the hand lever 54 at the forward position of the carriage or when the elbow has been completed. For purposes of adjustment, the contacting end of the arm includes a set screw and lock nut ar rangement indicated at 5?. Thus, the power may be connected to the main power shaft for the synchronizing movements of the machine either automatically or manually.

Carriage feed-ing mechanism The carriage 56 is slidably mounted on a mandrel 60. The mandrel consists of a heavy cylindrical member, extended longitudinally between the front and back brackets 23, 2 3, but only attached to the back bracket 26. For this purpose, the mandrel includes a head of at its rear end, fixed to the bracket by means of screws The forward end of the mandrel carries the interchangeable stationary die or forming disc 63, associated with the dies which corrugate the pipe.

The mandrel includes a longitudinally arranged spline groove 6d, within which a ratchet bar 65 is slidably disposed. This ratchet bar is normally held or urged rearwardly by springs at its front and rear ends. At the forward end, the splined groove is blocked by means of a stop 66 and a coil spring is disposed under compression between this stop and the forward end of the bar. At the rear end, a spring 61 is disposed under tension between a pin 68 on the head of the mandrel and a pin 69 fixed to the bar. The pin 69 is screw-threaded at its upper end and has its lower end fixed in the ratchet bar 65. The pin supports an eccentric to adjust the length of the return stroke of the bar 65. The pin 69 carries a nut to hold the eccentric 69a in any chosen position. The eccentric limits the return stroke of the bar 65 by abutting the head at the rear of the mandrel on the bars return stroke.

Now generally speaking, the feeding movements are imparted to the carriage (Figures 12, 15 and 14) by means of a mechanism imparting intermittent forward motion to the ratchet bar. This mechanism consists of an actuator 10 slidably mounted in vertical ways II on the back face of the rear bracket 24. The lower end of the actuator carries a roller I2 journalled on a pin I3. This roller rides on a cam ring I4, fixed to the driven clutch member 34 (Figure 16) The upper end of the actuator carries an adjustable contact finger I5 disposed at an angle to the ratchet bar 65 and engaging a roller I6, journalled in the bifurcated rear end of the bar where it extends through the bracket 24 (Figure 14). An adjustment screw 'I'I, held by a lock nut I8, changes the feeding stroke of the actuator by adjusting the finger "I5. This screw swings the finger on its pivot pin I9 and changes the position of the contact finger relative to the roller IE5. A cam action is imparted to the roller due to the angle of the finger.

To counteract the resultant upward thrust against the bar, a roller is carried in the bifurcated lower end of a bracket 8! fixed in a slot in the rear face of the main bracket 24, just above the bar. This roller provides a rolling contact for the bar as the reciprocatory movement is imparted. Thus, it will be seen that the actuator intermittently moves the ratchet bar forwardly a little more than the distance between the notches of the bar. bar, return it rapidly after each forward feed of the carriage,

The carriage consists of a cup-shaped cylindrical element housing a multiplicity of concentrically engaged or nested collars of different diameters (Figures 12 and 13). More specifically described, the body of the mandrel includes an inner hub 86 and an outer flange 81 forming a deep groove in which the collars 85 are contained. The hub includes a longitudinal groove 88 through which the ratchet bar may slide. The adjacent faces of the collars 85, the hub 86, and the flange 87 are annularly grooved for about half the length of the collars. This provides a series of annular grooves 89 into any one of which the pipe may be inserted depending on its size. Also, the outer adjacent portions of these elements are chamfered to provide flared openings for easy insertion of the end of the pipe.

The pipe is locked in this carriage in any selected groove by means of a pin 90 of appropriate length. A set of pins is provided, one for each collar. Now, as shown in Figure 12, pipe of large diameter is to be formed, whereas, in Figure 13, pipe of medium diameter is to be formed.

In order to provide a solid surface against which the pin 90 may engage the pipe, each collar is provided with two radial apertures 9I-9I. Each collar or cylinder is rotatably mounted and adjusted by means of the tool 92 shown in Figure 11. This tool provides spaced pins 93 engageable in apertures 94 in the outer faces of the collars and is used somewhat after the manner of a spanner wrench. A centering pin 95 (Figure 13) is inserted through the radial openings to align them. Now that collar, directly encircled by the pipe, is rotated to bring its opening, which normally receives the locking pin 90 into alignment with the centering pin, thus providing a blank surface against which the looking or clamping pin 98 may engage the pipe wall.

As stated, a series of pins -90 of different length The springs, active on the are provided, one for each annulus or collar. These pins are headed and are normally urged to release position by means of a coil spring 96, disposed under compression between the head of the pin and the base of a spring socket in the outer flange 8'! of the carriage. After the pipe end has been inserted in the appropriate groove, a hand lever 91 (Figure 12) is provided for sliding the carriage along the mandrel, for clamping the pipe in position in the carriage as well as for controlling the connection of the carriage to the ratchet bar.

This lever 91 is pivoted on the rear end of a fulcrumed lever 98, mounted on forked bracket 99 attached to the top of the carriage adjacent the pin 90. The forward end of the fulcrumed lever carries the contact screw I00, engaging the top or headed end of the pin 90. The hand lever is pivoted on a pin I 0| on the rear end of the fulcrumed lever and has its lower, rounded end disposed in engagement with the top of the carriage, particularly a contact plate I02. When the lever is pulled forwardly, it forces the rear end of the fulcrumed lever upwardly and causes the pin to bite into the pipe disposed in the groove of the carriage. In its full forward position, the hand lever is beyond dead center and will remain in this position, locking the clamping pin in position.

The hand lever includes a spring clip I03 having a hook I84 at its lower end. This hook cooperates with the hook at the upper end of a latch pin I05 vertically slidably mounted in the carriage. This pin has its lower end cooperating with the teeth of the ratchet bar. It is normally held downwardly by means of a coil spring I06 under tension between a pin IE! on the latch and a pin I08 on a plate fixed to the carriage.

When the lever is in the position shown in dot and dash lines at the left of the view, Figure 12, the catch III is engaged with the hook of the latch pin and the latch pin is still in engagement with the teeth of the bar. When the clamping pin is set, the latch is lifted, as shown in dot and dash lines in the right hand portion of the View. In this position, the latch pin is pulled out of operative connection with the ratchet bar and the carriage may be slid backwardly to its starting position. When it reaches its starting position, the spring clip I I33 encounters a fixed stop constituted by a horizontal screw carried by a bracket I09, fixed to the mandrel. This disengages the clip from the latch pin. It drops into engagement with the ratchet bar and forms the operative connection between the ratchet bar and the carriage. At the same time, operation of the clutch lever through the arm 55 permits clutching of the power to the shaft 21 and reciprocation of the ratchet bar ensues. Then, the carriage is fed forwardly intermittently following each corrugating action.

It will be seen that the hand lever 91 has a triple function. It is effective for clamping the pipe in position in the carriage, for uncoupling the carriage from the ratchet bar, and for bodily moving the carriage to starting position.

C'orrugating mechanism The forward end of the power shaft 21 has a crank element IIil, secured thereto. This crank element (Figure 5) provides two circular crank portions III, one for the upper die IE2 and the other for the lower die H3. The upper die I I2 is carried by a rectangular frame I I4 guided along its sides, through a dovetail arrangement, in

guide. strips II5 fixed to the forward side of the machine by means of screws H6. The side, top and bottom members of the frame are held together by means of keys I I1 and screws I I8. The upper and lower dies may be best described as in the form of guillotines. The upper die is fixed to the upper cross member by means of bolts H9 and consists of a single plate. The lower die consists of two plates indicated at I23I2II. The

lower die carrier is also rectangular and is mounted in dovetail grooves along the inside of the side member of the upper die frame.

The plates of this die straddle the plate of the upper die. These plates are attached to the cross member of the lower die frame by means of screws I2I and are spaced by means of a spacer plate or strip I22. Guides I23 engage around die plates H2 and I2EII2II at the point where they interengage and prevent deflection of the plates at this point. These guides are fixed to the outer frame member, and are carried therewith. Therefore, the lower plates cannot spread in the operation of corrugating the metal.

The lower cross piece of each frame, centrally thereof,'includes a wrist pin I24 to which the crank rod I25 for the particular movement is attached. Each crank rod includes a split bearing portion I23 encircling its particular crank shaft portion I I I. The rod I25 extends from the bearing portion and carries an element I28 engaged upon the particular wrist pin. These bearing elements I28 are adjustably attached to the rods by screw-threaded connections to the rods and are fixed in position by means of lock nuts I29. Theconnection to the lower wrist pin is spaced by means of a spacer sleeve I39 so as to provide the appropriate clearance for the upper die movement. Thus, it will be seen that the dies are brought together through power applied from the shaft 21.

Since the upper portion of the corrugation is crimped in the subsequent bending operation, the single plate is adequate for forming the corrugation. The spaced plate arrangement at the bottom provides a wider corrugation but, since the corrugation is subsequentlyadditionally widened by the bending operation the initial variation in the width of the corrugation portions top and bottom, is immaterial.

These dies act relative to the stationary internal die constituted by the disc 63. This disc is removably fixed to the forward end of the mandrel concentrically thereof by means of a screw I32. The disc 63 has a round forward edge and the forming dies press the metal around this edge to form the corrugation. The movement of the dies is synchronized with the movement of the feeding mechanism. The mandrel carries an abutment plate I33 near its upper edge. This plate functions as an anvil against which the upper die plate I I2 can flatten and crimp the overlapped edges of the stone pipe. If it were not for this plate, the double thickness of metal would not crimp as nicely into the sharp fold necessary for the inner curve of the standard elbow.

Elbow bending mechanism As stated, the bending mechanism is operated from the main shaft 21. The means, which acts upon the bending head I34 attached to the forward end of the pipe, is pivotally mounted on forward extensions I35 of the bed 29 of the machine. A treadle I36 constitutes the main part of the bending apparatus, and is actuated from the shaft 21. This treadle is pivoted at its forward end at each side on the extensions I35 on pivot bolts I31. It is generally rectangular in shape providing side arms I38 and a cross bar I39 at its rear end.

The cross bar I39 (Figure 18) carries a contact plate I40 crosswise of the machine. An arm I4I, fixed to the shaft 21, carries a roller I42, which swings against this contact plate in each rotation of the shaft. The contact plate is adjustably secured by means of a screw I43 traversing a slot lengthwise of the plate. The top of the plate, crosswise of the machine, is sloping so that an adjustment of the plate lengthwise of the cross piece I 39, changes the effective height of the contact surface, engaged by the rollers in the operation.

The treadle 'is suspended on springs at its actuated end. For this purpose, bolts I44 are fixed in the bed 20 and extend upwardly traversing the cross piece I39. Each bolt has a nut I 45 on its upper end. Coil springs I46 are disposed between the nuts I45 and the treadle. Coil springs I41 are disposed between the underside of the treadle and the bed.

The upper coil springs are heavier than the lower and tend to hold the bending means tightly against the bending head I34 at all times. These springs are adjusted so as to permit the treadle to come back against the action of the lower springs and the tendency of the elbow material to spring back slightly after it is bent.

At the forward end, the treadle includes upward extensions I48, between which a support bar I49 is fixed crosswise of the machine beyond the forward end thereof. A pair of arms indicated generally at I50 is fixed on the cross bar against rotation. This is accomplished by having the bar I49 flattened and the apertures in the arms correspondingly flattened. Set screws hold the arms in position against lateral displacement. Additionally, the arms are jointed to permit pivotal movement or spreading movement as the pipe, carrying the bending head is inserted into the machine. For this purpose, the lower elements I5I of the arms are bifurcated to provide cross grooves.

The main arm elements I52 are pivoted in these grooves on pins I53. They are held inwardly or at vertical position by means of leaf springs I54, engaging their outer sides and fixed to the attached arm elements I5I by means of screws I55. At the upper ends of the arms, deflecting plates I56 are attached on the inner surface of the arms and incline outwardly to provide a flared space into which the head may be inserted.

The head provides a sleeve (Figures 2 and 10) having laterally projected arms I51, the upper surfaces of which are disposed on a tangential line of the sleeve. From these upper surfaces, the under surfaces I53 of the arms curve downwardly and inwardly so as to be engaged by the bending arms regardless of the angle at which the bending collar is disposed in the formation of the elbow (Figure 5). The pipe is attached to this bending head by sliding it into position in the head. For this purpose, the bending head I34 consists of inner and outer sleeves I59I6II fixed together and providing therebetween an annular groove or slot I6I having a tapered entrance. One of these forming or bending heads is provided for pipe of each size, that is to say, there is one bending head component to each clamping collar of the carriage.

Operation In operating the machine, the procedure is as follows: First, the carriage 56 is arranged to receive the pipe. To do this, the spanner Wrench 92 must be used to rotate the appropriate clamping collar into position and the corresponding pin 90 inserted so as to cooperate with this collar (Figure 13). The centering pin 94 is utilized to fix the clamping rings in position and is removed I after performing this operation. Also, a bending disc or stationary die 63 at the front end of the mandrel corresponding to the diameter of the pipe is placed in position. The operator then picksup the bending head I34 appropriate to the pipe size and inserts the pipe end into this collar. The pipe and collar are then inserted as a unit between the bending arms. The pipe is slid over the stationary die 63 and its rear end is inserted in the appropriate groove of the carriage, in the instance shownin the outer groove (Figure 3).

The operator then pulls the lever 91 forwardly, thus setting the pin 9|] and fixing the pipe in the carriage. This movement also lifts the latch I05. Thereupon continuing to hold the lever 91, the operator slides these assembled parts, that is, carriage, pipe, and bending head rearwardly until the catch |03 on the lever encounters the pin I08, permitting the latch to drop into the ratchet bar. To start the bending operation, the operator moves the hand lever 54 rearwardly and the clutch is connected, due to engagement of the lever 55 with the dog thus rotating the shaft 48 and lifting the clutch actuating arm 42 from in back of the key 39 to allow the spring 40 to engage the key 39 with the clutching tooth 4|. The power then being coupled to the shaft 21, the following operations ensue in the described order:

First, the ratchet bar 64 is slid forwardly, moving the carriage forwardly with it a little more than the distance of a notch. This advances the pipe with respect to the corrugating dies. At this time, the dies are brought together through the crank shaft arrangement and form the corrugation, bending the metal around the stationary die 63. While the corrugating dies are still engaging the pipe, the bending arms are operated through the actuating arm |4| on the treadle and forced against the lateral extensions of the bending collar. This forces the upper or inner portion of the elbow inwardly and draws out the lower portion. Each bending Operation changes the angle of the bending collar until eventually its outer end moves from vertical position to horizontal position. This series of operations, that is, pipe feeding, corrugation and bending are repeated at a high rate of speed until the elbow is formed, at which time the carriage arm 55 encounters the lever 54 and through the dog 5| permits the clutch lever 42 to drop into the annular groove of the clutch element for engagement by the clutch pin, thereby declutching.-

The lever 91 is then pushed rearwardly to release the pin 90 and the pipe is released from the carriage and can be withdrawn from the machine in the form of an elbow.

From the above description, it will be apparent to one skilled in the art that the machine can be adjusted to form elbows of any desired bend, such as thirty degrees, forty-five degrees, and sixty degrees. The; automatic starting action imparted by the arm 55 may be changed to a hand starting action by moving the adjustable cams 5|] and 5| to a position back of the limit of the return stroke of the carriage and actuating the bar 52 by hand through the hand lever 5|.

Having described my invention, I claim:

1. In a machine of the class described, mechanism for bending pipe following the transverse corrugation thereof, said mechanism comprising, a bending head fixed to the forward end of the pipe, swinging arms adapted to engage and progressively tip said bending head, a pivotally mounted treadle carrying said arms, a power shaft, a treadle actuating arm fixed on said power shaft and adapted to depress said treadle upon each revolution of the shaft; said treadle actuating arm being in direct engagement with said treadle, and adjustment means for controlling the throw of said treadle.

2. In a machine of the class described; a bending mechanism comprising a collar fixed to the forward end of the pipe and including laterally projecting arms, a bell crank pivotally mounted on the machine and including a swinging end engaging the arms of said collar and a swinging end disposed longitudinally of the pipe beneath the same, a power shaft, a cam on the power shaft, and springs normally maintaining said last-named swinging end in position for holding the first-named swinging end against the arms of the collar, said cam adapted to engage said last-named swinging end intermittently.

3. In a machine of the class described, mechanism for bending pipe following the transverse corrugation thereof; comprising, a pivoted bell crank having swinging pipe bending arms and an actuating arm, said actuating arm having its end supported between springs, certain of which are stronger than the others for normally forcing the bending arms toward the pipe, rods for maintaining said springs in position, and a cam for depressing said actuating arm intermittently.

CHARLES J. HOLUB. 

